In the process of textile sizing, a composition usually called size, commonly in the form of an aqueous solution, is temporarily applied to individual textile warp yarn threads or strands to protect them from the physical abuse of the weaving knitting operation. Once the weaving or knitting operation is complete, the size is removed, preferably by washing in hot water. This type of sizing is not to be confused with the application of size to a finished textile fabric to stiffen it, to add weight, or for some other purpose.
A class of sizing agents that are applied as a melt and rigidify at room temperature are known as melt sizes or sometimes hot melt sizes. Melt size compositions of several types have been described in the patent literature and other literature as well, including compositions based upon wax or wax modified with a polymer or copolymer soluble in the wax. Blends of high molecular weight with low molecular weight ethylene/alpha, beta unsaturated carboxylic acid copolymers, such as blends of high with low molecular weight ethylene/acrylic acid copolymers, optionally with up to 50% by weight of a wax, are described in U.S. Pat. No. 4,136,069. Quick-setting, nonaqueous, water-extractable textile melt sizes composed of an intimate blend of from 42 to 58% by weight of an 80/20 ethylene/acrylic acid copolymer and from 58 to 42% by weight of wax derived by full hydrogenation of animal and plant tallows and oils, excluding castor wax, are described in U.S. Pat. No. 4,401,782. While ethylene/acrylic acid copolymers have been successfully blended with an equal weight of less expensive tallow wax, size removal by aqueous or alkali extraction may not be entirely acceptable. This is particularly true of the tallow component of the size. Residual (unremoved) tallow can have profound adverse effects on dyeability and pilling resistance.
It has been discovered that the hot melt size compositions of U.S. Pat. No. 4,401,782 may be improved in water solubility by the inclusion of an effective quantity of a surfactant. According to the present invention, approximately equal weight amounts of fully hydrogenated tallow-type triglyceride wax and a specific ethylene/acrylic acid copolymer are melted together with from 1% to 14% of sebacic acid or dodecanedioic acid and from 1 to 10% of a surfactant comprising a nonionic, ethylene and/or propylene oxide adduct of a C.sub.10-15 alcohol, as specified in more detail below, to form a superior textile melt size that has acceptable film strength and is easily removed from the yarn on completion of the textile processing operation. Optionally, the copolymer content may be further reduced to as low as about 35 percent by weight by incorporation of from about one to seven percent by weight of a hydrogenated tallow amide or other fatty acid amide.